The present invention relates to a hydraulic apparatus, such as a rotating crusher, comprising a hydraulic motor actuated via a power circuit linkable to the main hydraulic circuit of an earth-moving equipment, such as an excavator or an earth-moving equipment in general.
Among the accessories attachable to the arms of excavators and similar construction equipments, it is known to use milling apparatuses, typically known as milling heads or rotating crushers, formed by a pair of drums provided with a row of teeth.
Apparatuses of this type have the advantage of having increased versatility and efficiency, and are typically used in the field of facilities for constructing tunnels or, more generally, in the field of construction works for communication routes and in cutting blocks of stone.
An example of this type of apparatus is described in U.S. Pat. No. 6,626,500, which relates to a rotating cutter comprising a shell on which two rotating drums are supported. The drums are mounted on the same shaft, which is set in rotation by a hydraulic motor actuated by means of an oil supply provided by the construction equipment itself. The apparatus can be fixed to the arm of an excavator via a linking connector in such a way that the operator can displace and orient the cutter as desired so as to excavate in the required position.
One of the problems linked to rotating cutters is that rotor blockages often occur, typically because the variety of the material in terms of hardness and resistance to crushing is never homogeneous, just as the surface to be crushed is not homogeneous. This means that the energy needed for dealing with this material differs between the rotors, creating a greater energy requirement from the rotor which is subjected to higher stress. In these cases, it may actually be found that the construction equipment cannot provide a sufficient torque to keep the drums rotating, partly because they are both meshed to the same rotating shaft and because the torque supplied by the construction equipment is thus inevitably divided into two equal parts.
Therefore, in cases where only one of the two drums comes into contact with harder material, there is actually an inefficient torque distribution.
Further, since the two drums are rigidly interconnected by means of the transmission shaft, there is a significant transmission of stresses and vibrations both to the cutting structure and to the arm of the construction equipment, leading to low precision in the positioning of the arm and thus in the cutting operation, and to potential damage to the arm of the supporting equipment.
A further example of crushing apparatus is disclosed in U.S. Pat. No. 7,604,301, relating to grinder blender comprising two cylindrical drums operated by a respective hydraulic motor. A hydraulic fluid supply line receives hydraulic fluid under pressure from the rotary hydraulic manifold, and discharges the hydraulic fluid to a flow divider. The flow divider supplies hydraulic fluid equally to the two motors through respective high pressure lines.
Therefore, the technical problem addressed by the present invention is to provide a hydraulic apparatus which makes it possible to overcome the drawbacks mentioned above in relation to the known prior art.
This problem is solved by the hydraulic apparatus according to the invention.